The present invention relates to improvements in a system for a rotary engine of the type which basically consists of a cylinder inside of which, and in the axial sense, a drum rotates which is provided with vanes which fit against the internal wall of the cylinder. A shaft passes through the geometrical center of this cylinder, and about this vanes rotate freely at angles which are mutually independent. On this shaft there is provided, in a rigid manner, one or more cylindrical eccentric parts about which the drum, performing the function of the piston, rotates freely. Concentrically with the drum, a pinion is provided which is arranged laterally with respect to the drum, and concentrically with respect to the cylinder, and a crown wheel having internal teeth is arranged at the side of the cylinder, the teeth engaging with further teeth in one single plane. The drum is provided with openings in the axial sense, through which the vanes pass, and bearings are provided between these openings and the vanes which allow the vanes to slide with respect to each other so that the relative angle between them is able to change.
The present invention relates to an internal combustion engine which basically consists of a cylinder inside of which a drum rotates in the axial sense, the drum being provided with two types of motion, one of which is rotation about its own axis and the other of which is a translatory movement which the axis itself is obliged to perform, by virtue of particular mechanisms which are provided for in this invention, a path which in this case is not circular but rather is hypocycloidal, which is the feature which differentiates and characterizes this engine and provides it with certain special characteristics which distinguish its volumetric, thermal and mechanical performance, as well as its cyclic motion and the curves showing its operation.
One of the particular aims of the present invention is to provide the possibility of displacing the geometric axis of the drum or piston so that it performs a hypocycloidal translatory motion which in this particular case will be elliptical as a result of the gearing relationship.
One of the advantages resulting from a drum which is provided with this type of motion is that at the point in time when, together with the vanes, a chamber of minimum volume is constituted, this does not then swing about its center, but rather the point of swinging becomes displaced towards the rear portion with a degree of de-phasing which depends on the relationship between the two superimposed eccentricities. This makes it possible for the perimeter or side of the drum between two vanes to have a radius which is almost equal to that of the cylinder and further makes it possible to adjust this since the volume of the chamber when it is at its smallest size will tend towards zero and consequently the volumetric ratio will tend to infinity, thus making it possible to provide the drum with combustion chambers having the most suitable volume and located at the most suitable position. On the other hand, when ignition occurs with this system, the chamber will expand in a manner similar to that of a fan centered on the rear vane, as a result of which all the pressure which is now concentrated on the drum, imposes a positive expansive motion on it, and at practically all points from the beginning onwards.
A further aim of the invention is to arrange for the displacements of the drum and, as a result of this the volumetric ratios, to be unequal at the differing stages in the working cycle, so that it is possible for the stroke during the intake and exhaust periods to be less than that during the compression and combustion operations, or even for the strokes and swept volumes to all be different.
The main advantage of these unequal displacements of the piston or drum is that, as the travel during the combustion stage can be greater than that during the intake stage, without this affecting the compression ratio which may be very high, as, since the gases which have burnt or are in the process of combustion now for this reason having a greater volume and a larger degree of travel over which to perform their expansion, when the exhaust stage starts, the pressure existing in the chamber will consequently have been reduced and this difference in pressure is turned into driving power, as a result of which the energy yield is increased. Due to the fact that the cubic capacity of a volumetric engine is measured using the maximum capacity for induction at a particular point in the cycle, this increase in volume which is developed during the driving stroke does not affect the cubic capacity of the engine.
A further aim of the invention is to make it possible to locate the inlet and exhaust ports on one or both lateral walls which close the drum located within the cylinder so that, in this way, they can be opened or closed cyclically by the drum itself at the appropriate time, without there being any need, in order to provide for this, to have recourse to superfluous moving mechanisms or masses. This is possible because now that the paths described by the drum have been extended, by providing the elliptical motion of its center, the ports and also the openings which are provided laterally in the drum for this purpose can be constructed so as to have dimensions which are quite adequate for their correct operation.
The main advantages resulting from this mechanism which provides the drum with a special motion which changes its cycle of travel are: (a) it is possible to increase considerably the ratio of the eccentricity which leads to an increase in the volumetric capacity for the same overall volume or the volume of the cylinder, (b) it is possible to increase the compond force which acts perpendicularly on the arm of the crankshaft, mainly during the first half of the driving stroke when the pressure is at its greatest, (c) it is possible to increase the length and volume of expansion during the driving stroke with respect to the intake stroke, (d) it is possible to increase the compression ratio, (e) the effect is obtainable, when ignition occurs, that the sector of the drum located between two vanes does not tilt and become separated simultaneously at all points from the wall of the cylinder, these parts taken together constituting the same chamber, avoiding in this way spilling over which can make ignition extremely difficult, and thus making it possible to obtain a high degree of efficiency at the time of ignition or injection, (f) it is possible to eliminate every type of moving auxiliary mechanism or mass used for the specific function of opening or closing the ports or valves, (g) it is possible to provide communication in a very simple manner under working conditions between the inlet ports and the core of the drum since when the induction is performed through this, it is possible to cool and at the same time lubricate the vanes, the bearings, the drum and the other internal parts of the engine. Consequently, a better power output is achieved since the power developed by an engine is not only measured by the number of driving strokes per unit time but also by the degree of efficiency of these.
In one aspect of the invention, the drum is mounted on a crank or cranks and because of this, it is possible to eliminate the eccentric part(s) which is located on the shaft which passed through the geometrical center of the cylinder and which limited the degree of eccentricity of the drum with respect to the diameter of the cylinder. One essential characteristic of these cranks, which take on the function of eccentric parts, consists in the fact that they are followed by a second eccentric part which rotates cyclically in such a way that this is superimposed on the axis of eccentricity or arm of the crank in a direction of rotation which is the same as that of the drum. This rotation of the second eccentric part is produced since the arm of the crank which describes a circumference is not rigidly fixed, but rather rotates. This arm is basically made up by three elementary parts. The first consists of a cylinder, the axis of which is parallel to but eccentrically offset with respect to the axis of the arm, as a result of which it operates as a second eccentric part on which the drum is free to rotate by means of bearings. The second is made up by a spacing which is designed to house bearings which allows it to rotate about the geometrical center of the arm of the crank. The third part consists of a pinion arranged concentrically with respect to the arm and the effective diameter of which is equal to the rotational circular path described by its center, which is imposed upon it due to the rotation of the crank.
This pinion engages with an internally toothed crown wheel arranged concentrically with respect to the axis of rotation of the crank and the effective diameter of which is equal to twice the circumference described by the arm of the crank.
Using this gearing relationship the resulting effect is that when the crank has made one complete revolution, the pinion, which together with the second eccentric part constitutes its arm, will also have performed one complete revolution in the opposing sense, but when the second eccentric part has performed this complete revolution, or two revolutions with respect to the crank due to revolving in opposing senses, the drum which revolves about it will have performed one-third of a revolution in the same sense.
Independently of this gearing relationship between the pinion and the crown wheel which has just been described and which taken overall constitutes the crank system which is one particular feature of the invention, there is present, as is common with this type of motor, a pinion located on the drum or piston and arranged concentrically with respect to it and this engages with a circular crown wheel having internal toothing arranged concentrically with respect to the cylinder and which impresses on it, as a result of this gearing, a rotational motion which is in the reverse sense with respect to its orbit using a ratio of diameters which depends on the number of vanes, but more in particular, since the engine which is the object of the invention has the particular feature that the drum is mounted on a combination of superimposed or series connected eccentric parts as a result of which its axis does not describe a circular path, the pinion which is arranged concentrically with respect to the drum is not able to engage with a circular crown wheel, but rather in this case the latter must be provided with a hypocycloidal perimeter over which it engages, which in this particular case will be elliptical. The effective major radius of this elliptical crown wheel will be equal to four times the radius of eccentricity of the geometrical axis of the arm of the crank, plus the radius of eccentricity of the second eccentric part which is superimposed on this radius, and the minor effective radius will be equal to four times the radius of eccentricity of the arm of the crank minus the radius of eccentricity of the second eccentric part.
In order to clarify the basic concepts which characterize and substantially modify this type of engine, several sheets of drawings are attached to the present description which are provided solely by way of example, in which the most salient features of the invention are shown.